You want to try something interesting but want to dual-boot. That last bit could be difficult or "impossible" but using a VM or running from USB stick are options.
- https://www.haiku-os.org I've run it from USB stick on some older laptop.
- https://chimera-linux.org FreeBSD user-land with a Linux kernel.
- https://nomadbsd.org FreeBSD which can be run from USB stick with persistent storage. Has a version with ZFS support.
- https://nixos.org Very interesting concept.
- https://www.gobolinux.org GoboLinux is an alternative Linux distribution which redefines the entire filesystem hierarchy. Doesn't seem up to date but quite interesting. If I remember well you can have different versions of software installed at the same time. Let's say (making this up) Bash 1.1, 3.1 and 5.2
- https://bedrocklinux.org Bedrock Linux is a meta Linux distribution which allows users to mix-and-match components from other, typically incompatible distributions.